The power of a capsule of sugar to relieve depression or ease back pain is called the placebo response: as long as you believe you are taking medicine, you often get better. (Actually, placebo response even shows up in clinical trials when people are told the pill they are swallowing may or may not be the real thing.) But can a sugar pill fix a bad sex life?

That question was the focus of a study published yesterday in the online edition of The Journal of Sexual Medicine. The study focused on 50 women who had received a placebo instead of tadalafil in an old clinical trial for the drug, which is now sold as Cialis (and which wouldn’t have done much for the women anyway, since it’s an erectile-dysfunction drug). (More on Time.com: Photos: Sex and the City Fashion: What Not to Wear in the Office)

The authors of the paper — psychologists Andrea Bradford of Baylor College of Medicine in Texas and Cindy Meston of the University of Texas at Austin — crunched the numbers on the placebo arm of that trial and found that many women said their sex lives significantly improved when they were taking what they thought could be tadalafil. The women, ages 35 to 55 and all premenopausal, had all been diagnosed with female sexual arousal disorder. But after a few weeks on the placebo, the women as a group reported less distress and more fun in their sex lives.

But is this the power of placebo? The women also received some psychological treatment during the trial. It was not psychotherapy per se, but the women were asked to change their behavior: to try to have sex at least three times a month and to fill out detailed questionnaires about their sex lives. Pushing oneself to change regular patterns can be a potent treatment on its own. Also, filling out questionnaires forces you to self-monitor, which can be crucial to getting better.

Still, Bradford and Meston point out that in a four-week run-up period before the placebo was administered for the first time, the women did not improve with those behavioral interventions as much as they did after they started taking the sugar pill. Their rate of improvement also sped up after they started with the placebo. (More on Time.com: Top 10 Overplayed Wedding Songs)

What about men? A study published about a year ago in the same journal found that placebo can improve erectile function, particularly by increasing the quality of erections.

How? One way placebos work is that the people taking them tend to *want* to get better: the women in the current study were “highly motivated, as evidenced by their willingness to engage in regular sexual activity as a condition of enrollment.” The act of seeking treatment can often jump-start the body’s own natural healing powers.

But in this case, placebo probably works for sexual dysfunction because sex is virtually all in the head anyway. If you seek a better sex life, you might start with not taking a pill but figuring out exactly what pleases you.